Patent Literature 1 that is an example of a conventional technique discloses a car monitoring device for the purpose of “reducing the amount of data stored in the monitoring device, variably displaying data required for display on a car-by-car basis in accordance with the formation associated with the identification information for identifying the formation of cars, regardless of the type of formation of cars, and improving the performance of the monitoring device”. The car monitoring device includes: a unit configured to store in advance identification information for identifying a formation of cars including a combination of cars and instruments installed in the respective cars, and to store in advance data required for display in connection with each car; a unit configured to set the identification information of the formation of cars; a unit configured to select and edit data required for display of the cars that constitute the formation in accordance with the identification information; and a unit configured to display the data required for display in association with the cars that constitute the formation based on data for variable display of each screen.